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From: Oleg Nesterov <oleg@redhat.com>
To: Denys Vlasenko <dvlasenk@redhat.com>
Cc: linux-kernel@vger.kernel.org,
	Jan Kratochvil <jan.kratochvil@redhat.com>,
	"Dmitry V. Levin" <ldv@altlinux.org>
Subject: Re: [PATCH] ptrace: make PTRACE_DETACH work on non-stopped tracees.
Date: Wed, 19 Jun 2013 18:32:34 +0200	[thread overview]
Message-ID: <20130619163234.GA12029@redhat.com> (raw)
In-Reply-To: <1371654936-31742-1-git-send-email-dvlasenk@redhat.com>

On 06/19, Denys Vlasenko wrote:
>
> This is a user-visible behavior change.
> Do we really have to introduce a separate
> PTRACE_NOT_STUPID_DETACH? I hope not.

Oh, I think yes.

> @@ -1062,7 +1060,8 @@ SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
>  	}
>
>  	ret = ptrace_check_attach(child, request == PTRACE_KILL ||
> -				  request == PTRACE_INTERRUPT);
> +				  request == PTRACE_INTERRUPT ||
> +				  request == PTRACE_DETACH);

There doesn't look right.

For example ptrace_disable(). See the comment set_task_blockstep().
And flush_ptrace_hw_breakpoint() can race with the exiting task.

And the setting of ->exit_code is racy too.

And this makes the ptrace_unfreeze_traced() logic more confusing...
but probably this is fine.

Oleg.


  parent reply	other threads:[~2013-06-19 16:36 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-19 15:15 [PATCH] ptrace: make PTRACE_DETACH work on non-stopped tracees Denys Vlasenko
2013-06-19 16:09 ` Jan Kratochvil
2013-06-19 16:42   ` Pedro Alves
2013-06-19 16:52     ` Oleg Nesterov
2013-06-19 16:32 ` Oleg Nesterov [this message]
2013-06-19 23:19   ` Denys Vlasenko
2013-06-20 13:41     ` Oleg Nesterov

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